Biology subjects

Xue, J.

Publications and source records attributed to Xue, J..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Artificial light at night and an invasive snail synergistically enhance the invasion of a non-native macrophyte

Herbivory shapes plant invasion outcomes, yet its role in aquatic plant invasions under changing environmental conditions, such as artificial light at night (ALAN), remains poorly understood. We conducted three experiments using invasive macrophyte Myriophyllum aquaticum, a native macrophyte community (Vallisneria natans, Hydrilla verticillata, M. spicatum), invasive snail Pomacea canaliculata, and native snail Cipangopaludina chinensis to test the combined effects of ALAN and herbivory on non-native macrophyte invasions. ALAN increased M. aquaticum height and total biomass, but had no effect on native species growth. In feeding assays, P. canaliculata consumed all three native species but consistently avoided M. aquaticum under both light treatments. C. chinensis showed no feeding in no-choice assays, but in choice assays, consumed H. verticillata and M. spicatum under No-ALAN and only M. spicatum under ALAN. In community mesocosms, P. canaliculata reduced native macrophyte biomass by 48.0% under No-ALAN and 87.2% under ALAN without affecting M. aquaticum. This selective feeding increased M. aquaticums proportional biomass, with a stronger effect under ALAN than No-ALAN. These results suggest that ALAN can indirectly facilitate non-native macrophyte invasion by amplifying their relative biomass within native communities, particularly in the presence of invasive herbivores, and may promote invasional meltdown through altered feeding preferences.

ecology↗

bioRxiv2025

Epithelial FOXP3 Drives Pancreatic Fibrosis through O-glycosylated IL-6

BACKGROUND & AIMSThe transcription factor FOXP3, known for specifying regulatory T cell fate, is unexpectedly expressed in the epithelium of precancerous pancreatic lesions. Here we investigate its non-immune role in initiating pancreatic fibrosis, a process driving therapeutic resistance and organ failure in pancreatic ductal adenocarcinoma (PDAC) with unknown origins in early neoplasia. METHODSUsing human tissues and genetically engineered mouse models, we analysed FOXP3 expression in premalignant lesions. We employed epithelial-specific FOXP3 knockout and knock-in strategies to determine its functional impact on fibrogenesis and neoplasia progression. Mechanistic studies included chromatin immunoprecipitation, glycomic analyses, and signalling assays. RESULTSFOXP3 was consistently expressed in the epithelial compartment of human and murine precancerous pancreas. Epithelial-specific deletion of FOXP3 attenuated pancreatic fibrosis and delayed neoplasia, whereas its knock-in induced spontaneous stromal activation and accelerated PanIN progression. Mechanistically, epithelial FOXP3 directly transactivated the glycosyltransferase GALNT1. GALNT1, in turn, mediated O-glycosylation of interleukin (IL)-6, which was essential for its rapid secretion. CONCLUSIONSOur study establishes epithelial-derived FOXP3 as a master regulator of early pancreatic fibrocarcinogenesis. It drives a glycosylation-dependent amplification loop for IL-6 signalling, orchestrating sustained stromal activation. This pathway represents a promising target for intercepting pancreatic fibrosis and carcinogenesis at its origin.

cancer biology↗

bioRxiv2025

B Cell-Induced Lymph Node Stromal Remodeling Compromises Neutrophil Response to Secondary Staphylococcus aureus Infection

The lymph node (LN) stromal cells create niches, regulate lymph drainage, and guide the migration, positioning, and activation of immune cells within the LN. Upon stimulation, the stromal cells respond dynamically to accommodate the massive expansion of immune cells in the LN. However, there is still a limited understanding of how niche-associated stromal cell subsets are remodeled and how this remodeling reshapes host immune protection. In an oxazolone (OX)-induced skin inflammation model, we found that LN remodeling weakened the neutrophil response to secondary Staphylococcus aureus (S. aureus) infection in the inflamed LN, whereas depleting B cells rescued the responses. To understand the mechanism, we used single-cell RNA sequencing (scRNAseq) to characterize alterations in fibroblastic reticular cell (FRC) subsets and identified a new FRC subset expressing an intermediate level of CXCL13 (Cxcl13int RCs) in the inflamed LN. Further studies revealed that Cxcl13int RCs replaced Ccl19lo FRCs in the interfollicular zones (IFZs) of the inflamed LN, leading to a compromised conduit network. Depleting B cells preserved the integrity and function of the FRC-conduit network within the IFZ. Finally, the induction of Cxcl13int RCs depended on the B cell-derived lymphotoxin signaling. The induced Cxcl13int RCs were transitional, creating a time window of comprised immune protection during the OX-inflammation. This study elucidated a mechanism underlying LN stromal remodeling and provides proof-of-principle evidence that B cell-stromal interactions may be a novel target to enhance host immunity in diseased conditions.

immunology↗

bioRxiv2025

Recruitment of the outer-membrane lipoprotein DolP to thedivision site via cardiolipin-mediated diffusion-stateswitching

In diderm bacteria, the outer membrane (OM) must invaginate in step with septal peptidoglycan (PG) remodeling during cytokinesis. One OM lipoprotein, DolP, has been shown to localize at the cell division site and to facilitate the daughter cell separation. Yet how DolP is recruited to the division site remains unclear at the molecular level. Here, we show that DolP arrives concomitantly with the late divisome protein FtsN. Utilizing single-particle tracking Photoactivated Localization Microscopy (spt-PALM), we investigated the dynamics of individual DolP molecules in living Escherichia coli cells. Single-molecule analysis revealed two diffusion states: a diffusive state across the cell envelope and a previously underappreciated immobile state enriched at the septal and polar regions. Importantly, DolP does not comigrate with the processive FtsW-FtsI-FtsN complex. Mutations of the cardiolipin-binding surface caused loss of mid-cell enrichment and reduced the immobile fraction. Cardiolipins preference for high negative curvature enriches it at the division site, creating a trapping environment for DolP. Additionally, the active septal constriction but not the late divisome proteins recruit DolP. Together, these findings indicate that cardiolipin-mediated immobilization underlies DolPs septal enrichment.

microbiology↗

bioRxiv2025

Elevated plasma cholesterol causally improves sepsis outcome by promoting hepatic metabolic reprogramming

RationaleSepsis is a life-threatening condition with high mortality and limited therapeutic options. While hypocholesterolemia is associated with poor outcomes, the causal role of cholesterol and its underlying mechanisms remain unclear. ObjectivesTo determine whether elevated plasma cholesterol improves sepsis survival and to elucidate the mechanistic basis of this effect. MethodsWe analyzed septic patients from the MIMIC-IV database. Total cholesterol levels were compared between 28-day survivors and non-survivors using Wilcoxon rank-sum tests. Cox proportional hazards regression assessed the association between cholesterol levels and mortality, adjusting for age, sex, race, SOFA score, and Charlson comorbidity index. To establish causality, C57BL/6J mice were randomized to receive either a high-cholesterol diet (HCD) or regular diet (RD) for three days prior to cecal ligation and puncture (CLP) to induce sepsis. Measurements and Main ResultsSurvivors had significantly higher cholesterol levels than non-survivors (median, 135 vs. 126 mg/dL, p < 0.001). High cholesterol ([≥] 133 mg/dL) was independently associated with reduced 28-day mortality (adjusted HR = 0.80, 95% CI: 0.67-0.95, p = 0.012). In mice, HCD elevated plasma cholesterol and significantly improved survival (52.5% to 90%), independent of immune modulation.Hepatic transcriptomics revealed metabolic reprogramming, including upregulation of oxidative phosphorylation and glutathione-mediated antioxidant pathways, and suppression of endoplasmic reticulum proteostasis. Notably, inhibition of mitochondrial respiration abolished the survival benefit. ConclusionsElevated plasma cholesterol causally improves sepsis outcomes by promoting hepatic metabolic reprogramming. These findings offer mechanistic insight into clinical observations and suggest hepatic bioenergetics as a novel therapeutic target in sepsis.

physiology↗

bioRxiv2025

The role of medicinal Cu2+ salts in expanding the multi-pathway application of tigecycline against drug-resistant bacteria

Tetracyclines are highly susceptible to photolysis, causing pollution in water, land and other ecosystems, as well as posing threats to human health. In this study, we found that only tigecycline and minocycline reduce the antibacterial activity in light, and this inferiority has severely hindered their scope of clinical use. By strategically regulating the photolysis pathway, we identified chalcanthite, which primarily contains Cu2+. By conducting antibiotic susceptibility test and electron microscopy analysis, Cu2+ salts (including copper sulfate, copper chloride, and copper gluconate) were confirmed to restore the antibacterial activity of tigecycline under light exposure against all tested bacterial strains. Spectroscopic characterization combined with quantum chemical calculations elucidated the molecular mechanism by which Cu2+ selectively modulates the photolytic degradation pathway of tigecycline and structural determinants (dimethylamino groups on the D ring). Multi-omics technologies revealed the mechanism underlying the Cu2+-mediated (non-antibacterial) inhibition of bacterial ferric citrate transporter. Animal infection models were developed using diverse drug-resistant pathogens to validate the in vivo therapeutic efficacy of copper gluconate-tigecycline combination therapy under photic conditions. These findings revealed effective adjuvants that facilitate the development of topical tigecycline formulations, and the establishment of a scientific foundation for synthesizing photostable tetracycline-based antibiotics through structural optimization.

biochemistry↗

bioRxiv2025

Hydration Network Drives Activation and G Protein Selectivity in GPR174

G protein-coupled receptor 174 (GPR174), a key modulator of autoimmune responses, maintains immune homeostasis through distinct G protein signaling pathways, particularly Gs and Gi. Although the structural mechanism of lysophosphatidylserine (LysoPS)-activated GPR174 in the Gs pathway has been characterized, how hydration-mediated interactions influence GPR174 activation and signaling selectivity remains unclear. Here, we determined high-resolution cryo-electron microscopy (cryo-EM) structures of LysoPS-activated GPR174 bound to Gs (2.0 [A]) and Gi (3.4 [A]), revealing a continuous hydration-mediated signaling transduction network that bridges the sodium-binding pocket, NPxxY and DRY motifs, and the G protein-binding interface. This network stabilizes the active-state conformation of GPR174 and dynamically reshapes the intracellular cavity, thereby enabling differential engagement of Gs and Gi. Molecular dynamics simulations and functional assays demonstrated that the hydration network is essential for receptor activation and selectively modulates G protein coupling. To evaluate its conservation, we performed sequence alignment and structural analysis across class A GPCRs, defining three hydration cavities: the conserved water cavity (CWC), the junction water cavity (JWC), and the extended water cavity (EWC), whose hydration is determined by residue properties at position 5.58. Together, our study reveals a hydration-driven molecular mechanism that underlies the activation of GPR174 and its dual G protein selectivity. These findings advance the understanding of hydration-mediated signaling in GPR174 and provide a framework for investigating water-mediated regulation across class A GPCRs.

biophysics↗

bioRxiv2025

NQO1 phase condensation promotes stress granule assembly to facilitate pancreatic carcinogenesis

G3BP1 promotes pancreatic ductal adenocarcinoma (PDAC) tumorigenesis driven by oncogenic KRAS mutations through liquid-liquid phase separation (LLPS)-mediated assembly of stress granules (SGs). However, the regulatory mechanisms remain elusive. We identify the antioxidant enzyme NAD(P)H quinone dehydrogenase 1 (NQO1) as a novel SG regulator that enhances SG assembly in pancreatic cancer cells independently of reactive oxygen species (ROS). Mechanistic studies reveal that NQO1 does not regulate the expression of G3BP1 or other SG-associated genes. Instead, NQO1 undergoes LLPS dependent on its RNA-binding K homology (KH) like domain. Further analysis demonstrates that residues 121-131 of NQO1 directly interact with G3BP1s RNA-binding domain (RBD), enhancing the multivalency of G3BP1 complexes to potentiate LLPS-driven SG assembly. This interaction accelerates cell proliferation, KRAS mutation-induced acinar-to-ductal metaplasia (ADM), and pancreatic carcinogenesis. Notably, the interaction between NQO1 residues 121-131 and G3BP1s RBD is essential for NQO1 phase condensation under stress condition. Integrative analysis of human PDAC transcriptomic datasets reveals a weak association between NQO1 and G3BP1 levels. Importantly, both NQO1 and G3BP1 formed biological condensates and co-localized in the lesions of human PDAC tissue sections. Our study uncovers a novel KRAS mutation-driven mechanism of pancreatic carcinogenesis through the lens of phase separation, transcending conventional gene expression regulation and offering new insights into non-canonical KRAS-NQO1-G3BP1-SG regulatory networks in PDAC initiation.

cancer biology↗

bioRxiv2025

Disruption of the Wnt-antagonist Apc in the pituitary stem cells drives the development of adamantinomatous craniopharyngioma.

Adamantinomatous craniopharyngiomas (aCPs) are complex intracranial neoplasms that generally arise in the sellar and suprasellar region of the brain which affect the endocrine and nervous systems causing severe sequelae. Activating mutations resulting in degradation-resistant forms of {beta}-catenin (CTNNB1) have been shown to be the main driver for many of these neoplasms. However, the underlying genetic driver for a proportion of these tumours is still unknown. Using murine transgenic models, we show that genetic disruption of the Wnt-antagonist and tumour suppressor, adenomatous polyposis coli (Apc), within the pituitary progenitors/stem cells, leads to pituitary tumours that closely resemble human aCPs. These tumours present classic histopathological hallmarks of aCPs, such as large deposits of wet keratin, stellar-reticular-like cells, large cystic components and clusters of accumulating nucleo-cytoplasmic {beta}-catenin that are slow-dividing and exhibit a secretory phenotype. We show that a hypomorphic allele of Apc is sufficient for tumour development, indicating that disruption of Apc function can lead to aCP formation. Moreover, we identify that bi-allelic loss of Apc in the Sox2+ve pituitary stem cells is sufficient to initiate tumour formation, indicating that Sox2+ve stem cells are the cell origin of these Apc-driven aCPs. Transcriptomic analyses of early tumour-initiating cells revealed that Apc-driven clusters of accumulating {beta}-catenin undergo senescence-associated secretory phenotype (SASP), which is p21-mediated and results in secretion of inflammasome, angiosome and developmental growth factors. Our data unequivocally show a causal role for the disruption of the tumour suppressor Apc as a primary driver of aCPs independent of mutations in {beta}-catenin. We provide murine models representing a novel genetic subtype of human aCPs offering insights into aCP pathogenesis. Our work reinforces the importance of genetic testing for mutations in APC in patients with aCPs and identifies a potential need to screen patients with familial adenomatous polyposis (FAP) or spectrum of APC-pathogenic syndromes for aCPs in early life.

cancer biology↗

bioRxiv2025

Effects of combined prenatal exposure to air pollution and maternal stress on social behavior and oxytocin and vasopressin systems in male and female mice

Prenatal exposures to air pollution and maternal psychosocial stress are each associated with increased risk of neurodevelopmental disorders, including autism spectrum disorder (ASD) and epidemiological work suggests that concurrent exposure to these risk factors may be particularly harmful. This is important given that the same populations often bear the brunt of both toxicant and psychosocial stress burdens. Social impairments are a defining symptom in ASD. Previous work modeling combined prenatal exposure to diesel exhaust particles (DEP) and maternal stress (MS) in rodents has found male-biased social deficits in offspring, as well as changes to neuroimmune processes and the gut microbiome. However, the precise neural circuits on which these exposures converge to impact social behavior is unclear. Oxytocin (OXT) and vasopressin (AVP) are neuropeptides critical to the regulation of social behavior across species, signaling primarily at the oxytocin receptor (Oxtr) and vasopressin V1a receptor (V1aR) in the brain. Here, we hypothesized that OXT and/or AVP expression would be reduced in the brain following DEP/MS exposure. Following prenatal exposure to DEP/MS or the vehicle/control condition (VEH/CON), we measured maternal and offspring outcomes during the perinatal period, social and anxiety-like behavior during adolescence, OXT and AVP cell/fiber density and Oxtr and Avpr1a mRNA expression in early adulthood in several brain regions in both males and females. We observed a decrease in interaction time in DEP/MS males as compared to VEH/CON in the sociability assay and a decrease in social novelty preference in DEP/MS females as compared to VEH/CON. No effects of sex or treatment were observed on OXT or AVP cell number or fiber density in the hypothalamic regions assessed. However, numerous sex differences were observed in Oxtr and Avpr1a mRNA. Moreover, Avpr1a mRNA was significantly increased following DEP/MS exposure in the nucleus accumbens in both sexes and tended to increase in the dorsal hippocampus. Conversely, Avpr1a mRNA tended to decrease in the amygdala in both sexes following DEP/MS exposure. Together, these findings suggest that DEP/MS exposure has a stronger impact on female social behavior than previously observed. Moreover, while DEP/MS exposure does not appear to impact OXT or AVP expression in the brain, V1aR expression is modulated by DEP/MS exposure in several brain regions. HighlightsO_LIPrenatal DEP/MS reduces social novelty preference in females C_LIO_LIPrenatal DEP/MS does not alter OXT or AVP cell number in the PVN C_LIO_LIPrenatal DEP/MS does not alter OXT or AVP fiber density in the LH, AH, or MPOA C_LIO_LIPrenatal DEP/MS increases Avpr1a mRNA in the NAc C_LIO_LIPrenatal DEP/MS tends to decrease Avrp1a mRNA in the AMY and increase in dHipp C_LI

neuroscience↗

bioRxiv2025

Imagined Speech Reconstruction with 3D Neural Metabolism and Large Language Model Integration

Cognitive linguistics posits that language underpins human thought, and this principle has influenced the study and development of large language models (LLMs). In particular, several studies have investigated the metabolic costs of sentence formation using neuroimaging techniques such as positron emission tomography, functional magnetic resonance imaging, electroencephalography (EEG), and imagined speech reconstruction (ISR). In this study, EEG data corresponding to imagined English-language speech phonemes were used for ISR, in combination with an LLM trained on an abridged autobiography. The LLM-generated text responses guided the synthesis of EEG data from relevant phonemes, which were then used to estimate corresponding metabolic activity, and the changes in simulated neurometabolic and electrical parameters were visually represented. Notably, introducing pseudorandom variance significantly (p < 0.001) enhanced the models ability to reflect biological variability. Future directions include expanding the ISR system with lightweight or locally run LLMs, incorporating training data from larger and more diverse populations, and utilizing truly random variability sources. Further optimization for broader hardware compatibility and implementation--such as neural phantoms, emotional context integration, or human-computer interaction platforms--offer promising pathways for advancement. Overall, this work establishes a foundation for the next generation of biologically inspired, modular, and adaptable ISR systems for both research and practical applications.

neuroscience↗

bioRxiv2025

Germline de novo mutation rate of the highly heterozygous amphioxus genome

Germline de novo mutations (DNMs) are the ultimate source of heritable variation, yet their patterns in highly heterozygous genomes remain poorly understood. Amphioxus, an early-branching chordate with exceptionally high genomic heterozygosity (3.2[~]4.2% in sequenced species), offers a unique model to explore mutational dynamics in such contexts. It is unclear whether high heterozygosity in amphioxus is due to a large effective population size, an increased mutation rate, or both. Here, we perform deep short-read whole genome sequencing of a two-generation pedigree of the amphioxus Branchiostoma floridae comprising two parents and 104 offspring, and develop a framework based on allele-aware parental assemblies as the reference to accurately identify DNMs. We detect 205 high-confidence DNMs, yielding a genome-wide mutation rate of 5.10 x 10-9 per base per generation, which is comparable to that of vertebrates. Combining this estimate with observed nucleotide diversity, we obtain an effective population size of [~]1.9 million, indicating that the elevated heterozygosity mainly results from a large effective population size. We observe a maternal-origin bias when considering all DNMs but a paternal-origin bias for early-occurring ones. Amphioxus harbors a much smaller fraction of CpG>TpG DNMs relative to vertebrates, attributable to its low methylation levels. We also investigate putative post-zygotic mutations in the offspring, revealing an unexpected paternal-origin bias. These suggest some distinct mutational mechanisms in amphioxus. Our study not only provides the first DNM measurement for amphioxus but also offers a generalizable strategy for studying DNMs in highly heterozygous genomes, facilitating mutation rate studies across chordates and other lineages.

genomics↗

bioRxiv2025

Direct detection of meiotic recombination events in the highly heterozygous amphioxus genome

Amphioxus, a basal chordate with highly heterozygous genomes (3.2[~]4.2% in sequenced species), represents a key model for understanding vertebrate origins. However, the extreme heterozygosity poses challenges for many genomic analyses, including studying meiotic recombination. Here, we present a novel bioinformatic pipeline that enables direct detection of crossover (CO) and non-crossover (NCO) recombination events using short-read whole-genome sequencing of a two-generation pedigree (two parents and 104 F1 offspring) of the amphioxus Branchiostoma floridae. Using parental assemblies generated by Platanus-allee as a custom reference for read alignment, we tracked inheritance patterns in offspring and phased contig-level haplotypes in parents, allowing us to detect recombination events. We identified 2,329 paternal and 2,288 maternal COs, yielding recombination rates of 4.57 cM/Mb and 4.49 cM/Mb, respectively. We found CO coldspots spanning >140 Mb in each parent and these are likely associated with large-scale heterozygous inversions. CO rates were positively correlated with transposable element and gene density in both sexes, but showed weak or no correlation with GC content. We further identified [~]10,000 paternal and [~]5,800 maternal NCO events, predominantly shorter than 200 bp in tract length, and found evidence of GC-biased gene conversion. This work provides the first direct and genome-wide measurement of recombination in amphioxus and demonstrates how high heterozygosity, often considered a barrier, can be leveraged for fine-scale recombination mapping. Our findings illuminate conserved and divergent features of recombination in chordates and establish a framework for studying recombination in other highly heterozygous organisms.

genomics↗

bioRxiv2025

Genome-Wide Investigation of Transcription Factor Occupancy and Dynamics Using cFOOT-seq

Gene regulation relies on the precise binding of transcription factors (TFs) at regulatory elements, but simultaneously detecting hundreds of TFs on chromatin is challenging. We developed cFOOT-seq, a cytosine deaminase-based TF footprinting assay, for high-resolution, quantitative genome-wide assessment of TF binding in both open and closed chromatin, even with small cell numbers. By utilizing the dsDNA deaminase SsdAtox, cFOOT-seq converts accessible cytosines to uracil while preserving genomic integrity, making it compatible with techniques like ATAC-seq for sensitive and cost-effective detection of TF occupancy at single-molecule and single-cell level. Our approach enables the delineation of TF footprints, quantification of occupancy, and examination of chromatin influences. Notably, cFOOT-seq, combined with FootTrack analysis, predicts TF occupancy dynamics. We demonstrate its application in capturing cell type-specific TFs, analyzing TF dynamics during reprogramming, and revealing TF dependencies on chromatin remodelers. Overall, cFOOT-seq represents a robust approach for investigating the genome-wide dynamics of TF occupancy and elucidating the cis-regulatory architecture underlying gene regulation.

molecular biology↗

bioRxiv2025

Salmonella hijacks a host glucose transporter for intravacuolar proliferation

AbstractsSalmonella is an intracellular pathogen that resides within a vacuole, which protects it from cytosolic host defenses at the expense of limited nutrient access. Glucose serves as a critical carbon source supporting Salmonellas intracellular replication. However, the molecular mechanisms driving glucose enhancement and the pathways by which cytosolic glucose becomes accessible to intravacuolar Salmonella remain poorly understood. Here, we elucidate a sophisticated three-pronged strategy through which Salmonella hijacks GLUT1 to co-opt host glucose metabolism for pathogenic advantage. Firstly, Salmonella infection upregulates the glucose transporter GLUT1 by activating the MAPK signaling cascade, enhancing host glucose uptake, and accelerating glycolytic flux. Secondly, Salmonella redirects GLUT1 to the bacterial vacuolar membrane to establish a glucose-import conduit that facilitates bacterial acquisition of cytosolic glucose. Thirdly, K29-linked ubiquitination modifications on bacterial vacuolar membranes are a previously unrecognized regulatory mechanism that potentiates GLUT1 transporter activity. Inhibition of GLUT1 potentiates Salmonella-triggered innate immune responses and attenuates bacterial virulence in vitro (RAW264.7 macrophages) and in vivo (murine infection model). Collectively, these findings delineate a novel paradigm of metabolic hijacking, wherein Salmonella systematically rewires host glucose metabolic networks to support intracellular proliferation, providing new insights into host-directed antimicrobial interventions.

microbiology↗

bioRxiv2024

Elastase mediated white matter damage in cerebral small vessel disease: Microglia - neutrophils pas de deux

Cerebral small vessel disease (CSVD) leads to an extensive white matter damage associated with cognitive decline, yet the underlying damaging mechanisms remain incompletely understood. Here we established a positive correlation between plasma levels of serine proteinase elastase ELANE and periventricular white matter hyperintensity (PV-WMH) in a cohort of CSVD patients. In a CSVD murine model induced by bilateral carotid artery stenosis (BCAS), upregulated ELANE was detected both in microglia and peripheral blood neutrophils. Genetic ELANE deficiency significantly alleviated oligodendrocyte loss, thereby reducing white matter lesions (WMLs) as well as ameliorating sensorimotor and cognitive impairments in BCAS mice. In vitro studies demonstrated that ELANE triggered time-dependent and dose-dependent oligodendrocyte lineage cell death. Bone marrow transplantation showed that ELANE from microglia and peripheral blood both contributed to WML development and BCAS-induced neurological deficits. Mechanistically, ELANE, accumulated by oligodendrocytes, cleaved the phosphodiesterase domain of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase). Pharmacological inhibition of ELANE with Sivelestat reduced oligodendrocyte loss and WMLs leading to the restoration of white matter integrity and neurological improvements in BCAS mice. In post-mortem brain specimens of CSVD patients ELANE accumulated within WMLs being predominantly localized in microglia (and hence defined as microglial ELANE) rather than in the brain-infiltrating neutrophils. We therefore posit microglial ELANE as an instigator of whiter matter injury in CSVD and suggest its potential therapeutic relevance.

neuroscience↗

bioRxiv2024

Reduced expression of PER2 protein contrbutes to β1-AA induced cardiac autophagy rhythm disorder

It has been confirmed that heart failure may be linked to fluctuations in autophagy rhythm of cardiomyocytes throughout the day. It is known that circadian rhythms depend on the regulation of core biological clock proteins, with PER2 playing a crucial role. Our previous research has confirmed the presence of {beta}1-Adrenergic receptor autoantibodies ({beta}1-AA) could induce inhibition of myocardial autophagy, leading to cell death and heart failure. However, it remains unclear whether {beta}1-AA induces cardiac autophagy rhythm disorder by affecting PER2 expression. This study find that {beta}1-AA disrupts the autophagy rhythm in cardiomyocytes, primarily indicates by the decreased expression of the autophagy marker protein LC3; {beta}1-AA induces disruption of the rhythmic expression of PER2 protein in myocardial cells, mainly manifests by a decrease in PER2 protein expression; Metoprolol is employed to verify that the {beta}1-adrenergic receptor contributes to the reduction of Per2 protein caused by {beta}1-AA. Knocking down Per2 with lentivirus reduces the inhibition of LC3 expression caused by {beta}1-AA, while overexpressing Per2 in cardiomyocytes using lentivirus significantly restores {beta}1-AA-induced decline in LC3 expression. At the same time, mTORC1 activation is found to participate in {beta}1-AA-induced autophagy inhibition of cardiomyocytes after pretreatment with the mTORC1 inhibitor rapamycin. Furthermore, it is confirmed that the decreased expression of PER2 protein caused by {beta}1-AA disrupts the myocardial autophagy rhythm by promoting mTORC1 activation through lentiviruses that knock down or overexpress the Per2 gene. This study provides experimental basis for the precision treatment of cardiovascular diseases from the perspective of biological rhythm.

molecular biology↗

bioRxiv2024

Structural mechanisms of PIP2 activation and SEA0400 inhibition in human cardiac sodium-calcium exchanger NCX1

Na+/Ca2+ exchangers (NCXs) transport Ca2+ across the plasma membrane in exchange for Na+ and play a vital role in maintaining cellular Ca2+ homeostasis. Our previous structural study of human cardiac NCX1 (HsNCX1) reveals the overall architecture of the eukaryotic exchanger and the formation of the inactivation assembly by the intracellular regulatory domain that underlies the cytosolic Na+-dependent inactivation and Ca2+ activation of NCX1. Here we present the cryo-EM structures of HsNCX1 in complex with a physiological activator phosphatidylinositol 4,5-bisphosphate (PIP2), or pharmacological inhibitor SEA0400 that enhances the inactivation of the exchanger. We demonstrate that PIP2 binding stimulates NCX1 activity by inducing a conformational change at the interface between the TM and cytosolic domains that destabilizes the inactivation assembly. In contrast, SEA0400 binding in the TM domain of NCX1 stabilizes the exchanger in an inward-facing conformation that facilitates the formation of the inactivation assembly, thereby promoting the Na+-dependent inactivation of NCX1. Thus, this study reveals the structural basis of PIP2 activation and SEA0400 inhibition of NCX1 and provides some mechanistic understandings of cellular regulation and pharmacology of NCX family proteins.

biophysics↗